1. Field of the Invention
The present invention relates to a device for appropriately adjusting the height of a seat such as, for example, an automobile seat.
2. Description of the Related Art
A conventional height adjusting device for an automobile seat is disposed between an upper rail, which constitutes a seat sliding apparatus, and a seat cushion, and includes a small-diameter pinion mounted on an operating shaft, a large-diameter sector gear held in engagement with the pinion, and an operating lever mounted on the sector gear. In an attempt to adjust the height of the seat, the operating lever is operated up and down to rotate the pinion via the sector gear (see, for example, Patent Document 1).
This height adjusting device also includes a brake drum for preventing a vertical movement of a lifting mechanism. Even if the operating lever is operated, no brakes are applied to the lifting mechanism, but if a load is applied from the seat cushion side, the brake drum applies the brakes to the lifting mechanism.
Patent Document 1: Japanese Laid-Open Patent Publication No. 10-35332 (see FIG. 1)
However, the brake drum employed in the height adjusting device as disclosed in Patent Document 1 is of a friction type, and there is still room for improvement in terms of the operational feel. Also, the seat stiffness is not so high.